Since organopolysiloxanes have many excellent characteristics, organopolysiloxanes in various forms have been used frequently as a feel improver or a film-forming resin. For example, Patent Document 1 discloses a poly(N-acylalkyleneimine)-modified organopolysiloxane having a high elastic modulus and undergoing neither rupture nor plastic deformation within a range of a certain extensibility. According to this document, this organopolysiloxane is excellent in, for example, hair setting performance and retention property of the hair thus set, compared with conventional film-forming resins.